dmethvin, you are right: qSA and mS behave inconsistently. It depends if you switch focus by clicking on elements *within* the same page or if you click on another page/application and then click on an element.
But I think this is another issue, and probably an issue for the Webkit developers, because it does not occur on Firefox or Opera.

My issue is only about how to detect if a specific div has focus when the user clicks around on the same webpage. This is important for many web applications, especially for my current project, a rich text email writer webapp.

is(':active') works on all platform in 1.8.2, but not is(':focus').

I analized the problem on different browsers (mobile and desktop). The focus tests should always return "true", but they do not:

<DIV ce>

jQ 1.8.2

jQ 1.7.2

is(':focus')

qSA

mS

is(':focus')

qSA

mS

Webkit

false

false

false

false

false

false

Firefox 15

false

true

true

true

true

true

Opera 12

false

true

-

true

true

-

<textarea>

jQ 1.8.2

jQ 1.7.2

is(':focus')

qSA

mS

is(':focus')

qSA

mS

Webkit

true

false

false

false

false

false

Firefox 15

true

true

true

true

true

true

Opera 12

true

true

-

true

true

-

Conclusion: focus detection with is(':focus') works only well for textareas on all platforms, but not for divs. qSA and mS are not reliable, either.

Question: Is there a chance jQ can fix is(':focus') for DIVs as it has been done for textareas already?

Remark: I hope very much jQ can found a workaround over the inconsistencies between different browsers and implement a reliable is(':focus') behaviour. It is easier to use a jQ update than to wait for Apple to implement an updated Mobile Safari in iOS 6...